In their study, researchers looked at elderly men with a genetic variation that produces an enzyme responsible for the metabolism of alcohol that is up to 80 times less competent at doing the task.
It was associated with reduced alcohol use, "but it had no association with depression whatsoever," Prof Almeida said.
"The conclusion is that alcohol use neither causes nor prevents depression in older men.
"Our results also debunk the view that mild to moderate alcohol consumption may reduce the risk of depression."